Arizona State University intends to grow 61 percent, to 92,000 students, and to become a nationally recognized research university by 2020, according to a plan announced Thursday.

The plan outlines sweeping changes that include adding a campus in downtown Phoenix, assigning each campus academic specialties, and encouraging schools within the university to compete nationally rather than with Arizona's other state universities.

Redefining and enlarging Arizona State is crucial to serving Phoenix and Arizona as a whole, said Michael M. Crow, the university's president and a key shaper of the plan. Even with 57,000 students, "we don't yet have what a city this size should have," he said. "ASU has to move forward in significant ways."

Phoenix is expected by 2020 to grow from 3.5 million people to nearly 8 million, Mr. Crow said. Arizona State is the city's only research university, he said, and needs to grow to keep itself and the city vital both economically and intellectually. An essential element of the plan is having the university work closely with the private sector and the city to promote economic partnerships, he said.

Much of the enrollment growth would take place at a new fourth campus, to be located in downtown Phoenix. The urban campus would be "integrated into the fabric of the city" and spread around a number of existing and new buildings, said Phillip B. Gordon, the mayor of Phoenix. The look of the campus would emulate other urban campuses, he said, such as New York University.

The new campus would eventually enroll about 15,000 students and house programs such as public policy, nursing, communications, and continuing education. The plan lays out a provisional timeline in which initial financing of the campus would be ready by next January and the first buildings would be finished by 2005. The entire campus would be completed by 2010 and would include a light-rail system between it and the university's main campus, in Tempe, just east of Phoenix.

The plan envisions the Tempe campus as staying at roughly 50,000 students and becoming a nationally recognized research university. The university's East campus, in Mesa, would grow from 3,200 students to between 10,000 and 15,000 students and would focus on technology and applied sciences. The West campus, in northwestern Phoenix, would grow from 7,100 students to between 10,000 and 12,000 students and would be a liberal-arts college.

The entire project would cost hundreds of millions of dollars, Mr. Crow said. Much of that money would come from the university, he said, but Phoenix, nearby cities, and private industry would also provide a large amount.

Arizona State's proposal has a good chance of working because it plans out growth and appeals to the frugality of state lawmakers and voters, said David A. Longanecker, executive director of the Western Interstate Commission for Higher Education. "There's no doubt they have got to do something to expand their capacity," he said, and the plan's specific goals should make it cheaper and more efficient to do so.

The expansion and reorganization of the state's largest public university is part of a larger plan to redefine the missions of the state's three public universities, Mr. Longanecker said. Backed by the Arizona Board of Regents and state lawmakers, he said, the plan would make Arizona State an urban university with nationally ranked research in numerous fields. The University of Arizona would become a more-selective research university, and Northern Arizona University would focus on undergraduate education.